fix(printer): 修正照片打印产品数量设置

- 将照片打印产品的数量固定为1
- 保留购买次数为源ID列表的大小
- 确保每个照片打印项只计算一次数量

src/main/java/com/ycwl/basic/service/printer/impl/PrinterServiceImpl.java

@@ -2037,7 +2037,7 @@ public class PrinterServiceImpl implements PrinterService {
             ProductItem photoItem = new ProductItem();
             photoItem.setProductType(ProductType.PHOTO_PRINT);
             photoItem.setProductId(scenicId.toString());
-            photoItem.setQuantity(sourceIds.size());
+            photoItem.setQuantity(1);
             photoItem.setPurchaseCount(sourceIds.size());
             photoItem.setScenicId(scenicId.toString());
             productItems.add(photoItem);